What is functional programming language?

Haskell is often considered the "purest" functional language. It is known for its strong type system, lazy evaluation, and emphasis on mathematical concepts.

Using a functional programming language offers several advantages, particularly for certain types of applications and development practices:

• Functions are treated like any other data type, allowing them to be passed as arguments to other functions and returned as values.
• Data is generally treated as immutable, meaning it cannot be modified after creation. This helps prevent side effects and makes code easier to reason about.
• Recursion is a fundamental technique in FP for solving problems by breaking them down into smaller, similar subproblems.
• Functions can take other functions as arguments or return functions as results, enabling powerful abstractions.
• Expressions are evaluated only when their results are needed, potentially improving performance in specific scenarios.

They offer several advantages:

1. Conciseness and readability — Functional code can often be more concise and easier to understand due to its declarative nature.
2. Reliability — The absence of mutable state reduces the likelihood of bugs and makes code more predictable.
3. Parallelism — Functional languages are well-suited for parallel programming, as functions can be executed independently without shared state.
4. Testability — The declarative style, focusing on what should be done rather than how, and lack of side effects make testing easier.
5. Efficiency — Lazy evaluation can optimize performance, especially in certain scenarios.
6. Big data handling — Functional languages are widely used in big data frameworks (e.g., Apache Spark, Akka) because they manage concurrent tasks and scale efficiently.

Besides Haskell, as we mentioned above, there are other popular examples of functional programming languages. Here are they:

• Scala — designed for the Java Virtual Machine (JVM), offering a blend of object-oriented and functional programming features.
• Clojure — A dynamically typed language known for its interactive development environment (REPL) and focus on functional programming.
• Elixir — A language excelling in building concurrent and scalable applications, known for its focus on functional programming principles.
• F# — A statically typed functional language for the .NET platform, praised for its strong type system and integration with other .NET languages.
• Elm — A functional language for building user interfaces, known for its type system and predictable behavior.
• OCaml — A general-purpose programming language that combines functional and object-oriented programming paradigms.
• Lisp — One of the oldest languages, known for its flexibility and use in AI research. Lisp supports multiple paradigms but is heavily functional.